JPH0580654B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lens and shutter drive device in an autofocus, autoexposure lens shutter camera.

"Prior Art and its Problems" In a conventional lens shutter camera of this type, the lens driving spring and the shutter driving spring are charged in conjunction with film winding.
When taking a picture, the lens is first driven by the restoring force of the lens drive spring, and then stopped at the in-focus position via a mechanical latch mechanism based on distance information to the subject. The restoring force of the spring kept the shutter open, and when the appropriate amount of exposure was obtained, the shutter was closed.

Therefore, in this conventional device, an interlocking mechanism between the film winding mechanism and the charging mechanism for the lens and shutter springs is essential, making the mechanism complicated. Further, in order to charge these springs, a large amount of force is required for hoisting, which causes problems in operability in manual hoisting and in motor torque and power consumption in electric hoisting. Furthermore, with conventional equipment,
It is essential to use a governor that slows down the moving speed of the lens in order to accurately locate the stop position of the lens using the latch mechanism, and a governor that reduces the opening speed of the shutter to an appropriate speed to obtain accurate exposure. Furthermore, the mechanical structure becomes more complicated.

In addition, when the above-mentioned conventional device employs a flash automatic system, the flash fires at the point when the appropriate aperture value is expected to be reached during the shutter opening process, but the shutter charge spring force and A certain degree of variation in the characteristics of the governor mechanism is unavoidable, and as a result, the speed at which the shutter opens also varies, so the aperture accuracy at the time the flash fires also varies, which can result in inaccurate exposure. I can't.

``Object of the Invention'' The present invention is to provide a drive device that can solve the above-mentioned problems with conventional lens and shutter drive devices, has a simple mechanical structure, and can obtain high lens position accuracy and shutter accuracy. With the goal.

``Summary of the Invention'' The present invention is designed to obtain the driving force of the lens and shutter by the electromagnetic force of a single electromagnetic driving means, whereas the driving force of the lens and shutter, which relied on the spring force in the conventional device, is distributed from the neutral position to the left and right. In the lens drive area and the shutter drive area, there is a drive member that can rotate around the optical axis, and the optical axis is moved step by step from the initial position by reciprocating rotation of this drive member in the lens drive area. a lens drive mechanism that rotates around the optical axis; and a lens shutter drive mechanism that rotates about the optical axis in steps from a closed position toward an open position by reciprocating rotation of the drive member in a shutter drive area. , an electromagnetic device that rotates the driving member reciprocatingly in the lens driving area the number of times based on the subject distance information from the distance measuring device, and then reciprocatingly in the shutter driving area the number of times based on the subject brightness information from the photometry circuit; The present invention is characterized in that it includes a drive means and a return means for returning the lens and lens shutter to their initial positions via the drive member and the electromagnetic drive means.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows an embodiment of a lens and shutter driving device according to the present invention. In this figure, all the annular members are supported so as to be rotatable about the optical axis, but their support mechanisms (members) are not shown. In addition, the size (diameter) of each annular member is
For the convenience of drawing two-dimensionally, they are drawn differently, but the actual size can be determined by varying the position of each annular member in the optical axis direction.

On the outer periphery of the aperture 1 made around the optical axis 2,
An annular drive member 5 is rotatably supported.
This drive member 5 includes a drive arm 5a extending in the radial direction.
A substantially rectangular coil 4 symmetrical with respect to the axis of the arm 5a is provided at the tip of the drive arm 5a. This coil 4 has two sides 4a and 4 on its left and right sides.
b is located within the magnetic field of a pair of permanent magnets 3a and 3b fixed to a fixed part of the camera. Permanent magnet 3
The magnetic fields a and 3b can be strengthened, for example, by a yoke (not shown).

According to the above structure, when current is passed through the coil 4 in the forward and reverse directions, the drive arm 5a, that is, the drive member 5, is rotated in the forward and reverse directions due to the electromagnetic action with the permanent magnets 3a and 3b. The driving arm 5a is the left and right permanent magnet 3
Assuming that the position in the figure located at the center of a and 3b is the neutral position, the present invention defines the left rotation range of the drive member 5 from the neutral position as the lens drive area, and the right rotation as the shutter drive area, respectively. The lens and shutter are driven by the reciprocating rotation of the driving member 5 in the area. Note that in the following description, "fixed" means fixed to a fixed member of the lens system, that is, a non-moving member.

Therefore, first, the members on the lens drive side will be explained. The drive arm 5a of the drive member 5 has a lens drive pin 5b.
is implanted, and this lens drive pin 5b is
It is located within the notch 6e of the lens drive ring 6. The rotatable area of this lens drive ring 6 is the protrusion 6a.
The angle is restricted to a narrow range by a pair of stoppers 6c and 6d, and a tension spring 6b applied between the projection 6a and the fixed part gives it dextrorotation in the figure, and normally this projection 6a is in contact with the stopper 6c. In this state, the lens drive pin 5b is almost in contact with the left side surface of the notch 6e in the figure. This lens drive ring 6 is paired with the lens advancement ring 7. The lens advancing ring 7 works in conjunction with a well-known lens extending mechanism such as a helicoid or a cam (not shown), and determines the extending position of the lens according to its rotation angle. This lens stepping ring 7 is given dextrorotation by a spring (not shown), and its rotation end (initial position) is regulated by a stopper 7a. This initial position corresponds to, for example, the shortest photographing position or the infinite photographing position of the lens system.

Further, the lens stepping ring 7 is formed with a stepping tooth row 7b and a latch tooth row 7c of equal pitch. The advance lever 9 can be engaged.
This lens advancement bar 9 is rotated levorotically about the axis 8 by means of a spring means (not shown), that is, the advancement tooth row 7b
A rotational biasing force is applied in the direction of engagement with the
By rotating the lens driving ring 6 to the left, the lens advancing ring 7
However, in the initial position, the fixing pin 10 releases the meshing with the progressive tooth row 7b.

The latch tooth row 7c also meshes with the latch lever 11. The latch lever 11 is pivotally attached to a fixed shaft 12, and is given a rotation biasing force by a spring (not shown) in the dextrorotation direction shown in the figure, that is, in the direction of meshing with the latch tooth row 7c.
Prevents the lens advancement ring 7 from returning. This latch lever 11 has an elongated hole 11a, into which a pin 13a provided on a latch release lever 13 that rotates about a fixed shaft 14 is fitted. The latch release lever 13 has a release arm 13b that can be engaged with a latch release pin 7d implanted in the lens advancement ring 7, and when the lens advancement ring 7 is rotated to the maximum left, this release arm 13b is released. When pushed by the release pin 7d, the latch lever 11 is rotated counterclockwise around the fixed shaft 12, and the latch lever 1
1 and the latch tooth row 7c.

A latch lever 11 is provided on the outside of the lens advancement ring 7.
A release holding lever 15 is pivotally mounted on a shaft 16 for holding the latch in a non-meshing position with the latch tooth row 7c. This release holding lever 15 has an interlocking arm 15a bent in an L shape in a direction perpendicular to the plane of the paper at one end thereof,
A spring (not shown) urges the interlocking arm 15a to rotate in a direction in which it comes into contact with the end surface of the latch lever 11. The interlocking arm 15a is the latch lever 1
1 rotates to a non-meshing position with the latch tooth row 7c, it engages with the locking step portion 11b of the latch lever 11, and holds the latch lever 11 in a non-meshing position with the latch tooth row 7c. On the other hand, when the lens advancing ring 7 is unlatched and reciprocated to the initial position, it comes into contact with the other end of the release holding lever 15 and prevents it from engaging the interlocking arm 15a and the locking step 11b. A return pin 7e is implanted to rotate in the direction of release.

Next, the members on the lens shutter driving side will be explained. A shutter drive pin 5c is implanted in the drive arm 5a of the drive member 5, and the shutter drive pin 5c is located within the notch 17e of the shutter drive ring 17. The rotatable region of the shutter drive ring 17 includes a projection 17a and a pair of stoppers 17.
c and 17d, and a tension spring 17b hooked between the projection 17a and the fixed part gives it levorotation in the figure, and the projection 17a is normally in contact with the stopper 17c. ing. In this state, the shutter drive pin 5c is almost in contact with the right side surface of the notch 17e in the figure.
It is paired with 8. The shutter advancing ring 18 is linked with a well-known lens shutter mechanism (not shown), and its rotation angle determines the opening amount of a plurality of normally closed shutter blades arranged around the optical axis. This shutter step ring 18 is
A spring (not shown) provides left rotation as shown in the figure, and the end of rotation (initial position) is regulated by a stopper 18a. This initial position corresponds to a closed state of the shutter.

Further, the shutter step ring 18 is formed with a step tooth row 18b and a latch tooth row 18c of equal pitch. Advance lever 20
can be engaged. This shutter advancement lever 20
The shutter drive ring 1 is given a dextrorotary force about the shaft 19 by a spring means (not shown), that is, in the direction of meshing with the progressive tooth row 18b.
7 rotates the shutter advancing ring 18 together, but in the initial position, the fixing pin 21 releases the meshing with the advancing tooth row 18b.

The latch tooth row 18c also meshes with the latch lever 22. The latch lever 22 is pivotally attached to a fixed shaft 23, and is given a levorotatory force by a spring (not shown), that is, a rotation biasing force in the direction of meshing with the latch tooth row 18c. Prevents stepping ring 18 from returning.

The latch lever 22 is also formed with an interlocking convex portion 22a that can engage with the release protrusion 6f of the lens drive ring 6 on the opposite side of the tip claw. The latch lever 22 is connected to the latch lever 22 via the interlocking convex portion 22a by the protrusion 6f.
rotates and disengages from the rat tooth row 18c.

This apparatus having the above configuration operates as follows. The current flowing through the coil 4 now gives the drive member 5 a rotational force in the left direction (lens drive area) in the figure. The direction of is called the opposite direction.

In the initial state shown in the figure, the protrusion 6a of the lens drive ring 6 is in contact with the stopper 6c, and the protrusion 17a of the shutter drive ring 17 is in contact with the stopper 17c. In this state, the drive member 5 is in the neutral position in the figure, and the lens drive pin 5b is connected to the lens drive ring 6.
The shutter drive pin 5c is located on the left side of the notch 6e, and the shutter drive pin 5c is located on the right side of the notch 17e. The lens advancement lever 9 is connected to the advancement tooth row 7b of the lens advancement ring 7.
are not engaged. The shutter advancement lever 20 is not engaged with the advancement tooth row 18b of the shutter advancement ring 18. When the lens advancing ring 7 is also at the initial position determined by the stopper 7a, the lens system is at the shortest photographing position or at the infinite photographing position, and the shutter advancing ring 18 is at the initial position determined by the stopper 18a. The shutters are closed.

When a positive current of sufficient magnitude is applied to the coil 4 from this state, a left rotational force is generated in the drive member 5, the lens drive pin 5b pushes the left side of the notch 6e, and the lens drive ring 6 is pulled by the tension spring. 6b until the protrusion 6a abuts against the stopper 6d. At this time, the lens stepping lever 9 meshes with the stepping tooth row 7b as the lens driving ring 6 rotates to the left, and pushes the lens stepping ring 7 to the left by one tooth of the stepping tooth row 7b. The latch lever 11 has a latch tooth row 7
Apply the latch to the next tooth in c.

When the coil 4 is de-energized, the lens driving ring 6 is returned to the position determined by the stopper 6c by the tension spring 6b, but since the lens advancing ring 7 is latched by the latch lever 11, the advancing tooth It remains stopped at the position rotated to the left by one tooth in row 7b. In other words, when the coil 4 is energized once in the positive direction, the progressive tooth row 7
The progressive lens movement corresponds to the rotation angle of one tooth of latch tooth row 7c. Therefore, since the lens moves step by step from the initial position in accordance with the number of pulses of the positive direction current applied to the coil 4, the object distance signal from a well-known distance measuring device (not shown) is converted into the number of pulses. If the power is applied to the coil 4 at a predetermined period, the lens will move to the in-focus position at the predetermined speed.

Next, when a sufficiently large reverse current is applied to the coil 4, a clockwise rotational force is generated in the drive member 5, and the shutter drive pin 5c pushes the right side of the notch 17e.
The shutter drive ring 17 is rotated against the tension spring 17b until its protrusion 17a abuts against the stopper 17d. At this time, the shutter advancement lever 20
As the shutter driving ring 17 rotates clockwise, the shutter advancing ring 18 meshes with the stepping tooth row 18b of the shutter stepping ring 18, and pushes the shutter stepping ring 18 to the right by one tooth of the stepping tooth row 18b. The latch lever 22 has the latch tooth row 1
Apply the latch to the next tooth in 8c.

When the coil 4 is de-energized, the shutter drive ring 17 is moved to the stopper 17 by the tension spring 17b.
However, since the shutter advancing ring 18 is latched by the latch lever 22, it remains stopped at a position rotated to the left by one tooth of the advancing tooth row 18b. . In other words, when the coil 4 is energized once in the reverse direction, the shutter opening amount corresponding to the rotation angle of one tooth of the progressive tooth row 18b (latch tooth row 18c) is obtained. If a plurality of reverse direction pulses are applied, a shutter opening amount that increases step by step according to the number of pulses can be obtained. Therefore, by converting the subject brightness signal from a well-known photometry device (not shown) into the number of pulses,
When applied to the coil 4 at a predetermined period, the shutter opens step by step at the predetermined speed.

When the shutter is opened to provide proper exposure, when a positive pulse current is applied to the coil 4, the shutter drive ring 17 returns to its initial position, and then the lens drive ring 6 rotates to the left. At the initial stage of leftward rotation of the lens drive ring 6, the release protrusion 6f provided on the lens drive ring 6 pushes down the rear part of the latch lever 22 and releases the latch of the shutter advancement ring 18. Then, since the shutter advancing ring 18 is given levorotation by a spring (not shown), the spring force causes it to rapidly return to its initial position, and the shutter also returns to its closed state.

When the lens drive ring 6 further rotates to the left,
The lens stepping ring 7 rotates by one tooth of the stepping tooth row 7b. That is, by applying pulse current to the coil 4 in the positive direction, the lens position at that point in time changes further step by step. The direction of this change is the same as when driving the lens for the first time, from the shortest photographing distance side (or the infinite photographing distance side) to the infinite photographing distance side (or the shortest photographing distance side). and,
When the latch release pin 7d implanted in the lens advancement ring 7 pushes the release arm 13b of the latch release lever 13 due to some pulse energization, the pin 13a lifts the latch lever 11 and releases the release holding lever 15.
The interlocking arm 15a falls into the locking step 11b of the latch lever 11 and holds the latch lever 11 in the unlatched state.

When the coil current stops in this state, the lens drive ring 6 returns to its initial position and the stepping lever 9 is removed from the stepping tooth row 7b. Therefore, the lens advancing ring 7 returns to its initial position, and in conjunction with this, the lens also returns to its initial position. Immediately before the lens advancing ring 7 returns to its initial position, the return pin 7e implanted in the lens advancing ring 7 pushes the release holding lever 15 and releases the engagement with the locking stepped portion 11b of the latch lever 11. Return the latch lever 11 to the latchable state. This completes the series of operations and prepares for the next shot.

FIG. 2 is a timing chart showing a series of operations from the shutter release operation when the device of the present invention is incorporated into a camera. In the figure, A indicates the state of energization of the forward and reverse pulse currents to the coil 4, B indicates the stepwise movement amount of the lens, and C indicates the shutter opening amount. First, when the shutter is released, the distance measurement and photometry circuits in the camera operate in the distance measurement and photometry period a, measure the subject distance and subject brightness, and calculate the number of pulses corresponding to each. Next, in the lens step interval b, a positive direction current of the number of pulses calculated by the distance measuring circuit is applied to the coil 4, and the lens is moved forward. When the lens has finished extending, the shutter advance section c
At this point, a reverse current equal to the number of pulses calculated by the photometric circuit is applied to the coil 4 to open the shutter in steps. Thereafter, when a predetermined number of pulses of positive current is applied to the coil 4, the shutter is restored and exposure is performed (shutter restoration period d).

When the exposure is completed, pulse current is further applied to the coil 4 in the positive direction (lens step period e), and when the lens reaches its end of movement, it returns to its initial position (lens return period f), and the next photograph is taken. It becomes possible.

Note that it is preferable that the width and period of the pulse applied to the coil 4 when stepping the shutter be narrower and faster than those when stepping the lens. This is because a shutter has a smaller inertia than a lens and can operate at high speed, as well as high exposure accuracy by driving with narrowly spaced pulses.

In addition, when performing flash photography with the device of the present invention, the subject distance obtained by the distance measuring device is converted into the number of shutter drive pulses that will give an appropriate aperture value, and the coil is Accurate exposure can be achieved by energizing the flash in the opposite direction and causing the flash to emit light.

"Effects of the Invention" As described above, according to the lens and shutter drive device of the present invention, since the lens position and the shutter opening are controlled by the electromagnetic drive means,
Extremely accurate. In addition, the lens drive mechanism, lens shutter drive mechanism, and the drive member and electromagnetic drive member that drive them rotate around the optical axis, and the lens position can be determined by the sequential operation of a single electromagnetic drive member. Since it is possible to perform a series of operations from 1 to 2 to determine the shutter aperture, it is possible to obtain a lens shutter camera that has a simple mechanical configuration, is compact, and has low manufacturing costs, and is compact, inexpensive, and highly accurate as a whole. can.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the lens and shutter driving device of the present invention, and FIG. 2 is a timing chart showing an example of the operation of a camera having the device shown in FIG. 1...Aperture, 2...Optical axis, 3a, 3b...Permanent magnet, 4...Coil, 5...Driving member, 5a...
Drive arm, 5b... Lens drive pin, 5c... Shutter drive pin, 6... Lens drive ring, 6c, 6d
... Stopper, 7... Lens advancement ring, 7a... Stopper, 7b... Increment tooth row, 7c... Latch tooth row, 9... Lens advancement lever, 11... Latch lever, 13... Latch release. Lever, 15...Release holding lever, 17...Shutter drive ring, 18...
Shutter step ring, 18a...stopper, 18b...
...Stepping tooth row, 18c... Latch tooth row, 20... Shutter step lever, 22... Latch lever.

Claims (1)

[Claims] 1. A drive member that is rotatably movable around an optical axis within a lens drive area and a shutter drive area that are distributed left and right from a neutral position; A reciprocating rotation of this drive member in the lens drive area a lens drive mechanism that is rotated step by step from an initial position about the optical axis; and a lens drive mechanism that is rotated step by step from a closed position toward an open position by reciprocating rotation of the drive member in a shutter drive region; , a lens shutter drive mechanism that rotates about the optical axis; and after the drive member is rotated back and forth in the lens drive area the number of times based on the subject distance information from the distance measuring device, the subject brightness is measured from the photometry circuit. An electromagnetic drive means for reciprocating the shutter within the shutter drive area a number of times based on the information; and a return means for returning the lens and shutter to their initial positions via the drive member and the electromagnetic drive means. A lens and shutter drive device having: